The latest thunderbird-52.5.0 is now available to upgrade to. This one does include a critical security fix.

Security vulnerabilities fixed in Thunderbird 52.5
ANNOUNCED
November 23, 2017
IMPACT
CRITICAL
PRODUCTS
Thunderbird
FIXED IN
Thunderbird 52.5
In general, these flaws cannot be exploited through email in the Thunderbird product because scripting is disabled when reading mail, but are potentially risks in browser or browser-like contexts.

#CVE-2017-7828: Use-after-free of PressShell while restyling layout

REPORTER
Nils
IMPACT
CRITICAL
Description

A use-after-free vulnerability can occur when flushing and resizing layout because the PressShell object has been freed while still in use. This results in a potentially exploitable crash during these operations.